Someone just wanted to animate boxes in diagonally. The key is mapping ℕ✕ℕ → ℕ by the Cantor pairing function!
This does not depend on data initially being sorted, or in any particular shape or arrangement; it could be square, rectangular, sparse, etc.
See also:
- Straight diagonal using comparator on existing data
- Stepped diagonal using Cantor pairing comparator on existing data
- Zigzag diagonal using alternating Cantor pairing comparator on existing data
- Generating by triangular numbers